Question alltel/sprint

[scheel78]

I have a sprint vogue. I am running sprint's latest radio and a tf2d custom rom. I ran alltel carrier cab and have it acivated on alltel. data, voice, sms,mms all work fine. when i use any of alltel's prl I have a roaming triangle and my phone says digital roaming. when I use any of sprint's prls I don't have a roaming triangle and it says alltel in the upper right corner of my phone. So which prl should I use. I've used both prls for about a month each without getting charged anything extra on my bill. I've heard that if you roam for more than 50% of the time they can charge you. Any insight would be appreciated